1. Field of the Invention natural gas or propane under pressure from a fixed pipe to a gas cooking appliance which is moveable on casters toward and from the fixed pipe. The apparatus is for use in the food service industry. It includes a connector coupled to a swivel for connecting a source of natural gas or propane to the gas appliance.
2. Description of the Prior Art
Gas appliance connector assemblies currently are being used in the food service industry. These assemblies are used to connect cooking appliances to a source of natural gas or propane under pressure. The source of gas supply comes from a fixed or stationary pipe having a shut off valve. The fixed pipe is usually mounted on or extends from a wall surface. This type of system is found in a large or commercial kitchen environment where the cooking appliance has heavy continuous use throughout the day. The appliance may be a fryer, range, grill or other type of cooking appliance. Usually, many of these appliances are located together. It is not uncommon to have fryers, numerous grills and other cooking equipment together. This equipment causes substantial grease and dirt deposits in the area of the appliance. The gas cooking appliance needs regular daily cleaning and the floor under it and the wall adjacent to the appliance need regular cleaning to keep grease from building with dirt, grime and food deposits causing sanitation problems. To clean the area and the appliance it must be moved. Large casters under the appliance permit easy movement. Floor space is at a premium in commercial kitchens, kitchens in restaurants and fast food enterprises. To accommodate the premium floor space, the cooking appliance is often moved as close to the wall with the fixed pipe as possible. This is shown in FIG. 1 (Prior Art). This causes major problems in the connector which bends and reverse bends in moving the appliance away from the wall and toward the wall. These repeated bends and reverse bends cause work hardening which causes the connector to break.
FIG. 1 shows a fixed pipe 10 extending from a wall 12. The pipe 10 has a 90.degree. street elbow 14 coupled to a shut-off valve 6 which has a handle 18. Coupled to the shut-off valve 16 is a connector 20 with nut 22. The opposite end of the connector 20 is coupled by nut 24 to a quick-disconnect device 26 which in turn is coupled to a 90.degree. street elbow 28 to the pipe 30 of a gas cooking appliance 32. The gas appliance 32 has casters 34 to facilitate easy movement of the gas appliance 32 away from the wall 12 and into various locations. This enables one to clean the area occupied by the gas appliance 32. A safety chain 36 attached to the wall 12 and the appliance 32 restrains appliance 32 to a movement to a maximum of six feet from the fixed pipe 10. The appliance 32 is pushed against the wall 12 as close as possible to conserve scarce floor space and in doing so causes a bend 38 in the connector 20.
The connector 20 is made in accordance with the American National Standard for Connectors for Movable Gas Appliances, approved Mar. 10, 1987 by the American National Standards Institute, Inc. ANSI Z 21.69-1987. The ANSI Z 21.69-1987 standard publication is incorporated by reference as to Part I CONSTRUCTION, Part II PERFORMANCE and Part IV DEFINITIONS. Part II provides under Section 2.6 TENSION AND FLEXURE STRENGTH that a connector shall withstand 100 cycles of flexing without leakage in excess of 10 cubic centimeters per hour while subjected to a lengthwise pull of 300 pounds per inch (52.5 KN/m) of nominal tubing diameter. Section 2.7 TORSION STRENGTH--provides that a connector shall withstand 30 applications of a twisting force applied in alternate directions without damage to the tubing or fittings or leakage in excess of 10 cubic centimeters per hour. Part IV provides that a corrugated connector is a metal connector having the gas conduit fabricated of metal tubing formed into helical or annular corrugations. It further provides that a quick disconnect device is a hand operated device which provides a means for connecting and disconnecting an appliance or an appliance connector to a gas supply and which is equipped with an automatic means to shut off the gas supply when the device is disconnected.
The quick-disconnect device 26 for quickly disconnecting the connector 20 from the 90.degree. street elbow 28 connecting the pipe 30 of the gas appliance 32 is made in accordance with American National Standard for Quick-Disconnect Devices for Use with Gas Fuel, approved Jan. 16, 1989 by the American National Standards Institute, Inc. ANSI Z 21.41-1989. ANSI Z 21.41-1989 standard publication is incorporated by reference as to Part I CONSTRUCTION--providing: the scope of the device which provides a means for connecting and disconnecting appliances or appliance connectors to gas supplies; the operation of the device which shall not require the use of tools to either connect or disconnect the devices; and the assembly which provides that the mating parts cannot be assembled incorrectly, unless such incorrect assembly would not permit the gas to flow.
The connector 20 is made of stainless steel tubing. It is corrugated. The connectors range in diameter from 1/4" to 11/4" and at lengths from 12" to 72". This connector 20 is designed to withstand high levels of stress and torsion with the quick-disconnect coupling 26. The tubing forming the connector 20 is corrugated and is flexible. The connectors 20 have a stainless steel braid over which a plastic coating is applied. Other types of connectors 20 do not have the coating but do have the braid covering it. This design was made to meet the demanding needs of the food service industry. The connector 20 allowed the use of casters 34 for the movement of commercial appliances 32 such as fryers, ovens and ranges. This type of connector 20 is used with the quick-disconnect 26 and the shut-off valve 16. This system is now the industry standard.
The connector 20, however, develops stresses when the gas appliance 32 is pulled away from the wall 12 as shown in FIG. 1A.
The bend 40 in the connector 20 in FIG. 1A and the bend 42 in FIG. 1A occur when the appliance 32 is pulled away from the wall 12 to permit cleaning the area previously occupied by the appliance 32. These bends 40 and 42 wrinkle the plastic coating as shown in the drawing and place extreme stresses on the connector 20 which when repeated daily cause the connector 20 to work harden and then to break and leak gas which results in a shortened life of the connector 20 and a dangerous condition.
Whenever the floor area is cleaned between the wall 12 and the appliance 32, the wall 12 area adjacent the appliance 32 is also cleaned and the appliance 32 itself is cleaned. After cleaning, the appliance 32 is rolled back toward the wall 12 and is pushed toward the wall 12 as far as it will move. The torsion forces in the connector 20 can have a tendency to resist this movement toward the wall 12. The daily frequent movement of the appliance 32 away from the wall 12 and back toward the wall 12 again causes extreme bends in the connector 20. Eventually this causes work hardening of the steel and the connector 20 breaks causing a gas leak. Also, the appliance 32 is frequently moved laterally in a diagonal away from the wall 12 instead of directly perpendicularly away from the wall 12. This causes bending and torsion stresses in the connector 20.
It is easier for the maintenance and cleaning personnel to leave the connector 20 connected to the appliance 32 rather than to disconnect the connector 20 from the appliance 32 using the quick-disconnect device 26. Therefore, most of the time rather than disconnect the connector 20 from the gas appliance 32 the cleaning and maintenance personnel leave the connector 20 coupled to the gas appliance 32.
It is this particular problem which causes the excessive bend stresses in the connector 20 and the torsion forces in the connector 20 which is coupled from a fixed pipe 10 extending from a wall 12 surface to a gas moveable cooking appliance 32 on casters 34 which the inventor solved with his new combination of elements.